ZyXEL Communications 5 Series - Manual (Page 428)

ZyWALL 5/35/70 Series User’s Guide
428 Chapter 24 Bandwidth Management
24.8 Bandwidth Borrowing
Bandwidth borrowing allows a sub-class to borrow unused bandwidth from its parent class,
whereas maximize bandwidth usage allows bandwidth classes to borrow any unused or
unbudgeted bandwidth on the whole interface.
Enable bandwidth borrowing on a sub-class to allow the sub-class to use its parent class’s
unused bandwidth. A parent class’s unused bandwidth is given to the highest priority sub-class
first. The sub-class can also borrow bandwidth from a higher parent class (grandparent class)
if the sub-class’s parent class is also configured to borrow bandwidth from its parent class.
This can go on for as many levels as are configured to borrow bandwidth from their parent
class (see
Section 24.8.1 on page 428 ).
The total of the bandwidth allotments for sub-classes cannot exceed the bandwidth allotment
of their parent class. The ZyWALL uses the scheduler to divide a parent class’s unused
bandwidth among the sub-classes.
24.8.1 Bandwidth Borrowing Example
Here is an example of bandwidth management with classes configured for bandwidth
borrowing. The classes are set up based on departments and individuals within certain
departments.
Refer to the product specifications in the appendix to see how many class levels you can
configure on your ZyWALL.
• The Bill class can borrow unused bandwidth from the Sales USA class because the Bill
class has bandwidth borrowing enabled.
• The Bill class can also borrow unused bandwidth from the Sales class because the Sales
USA class also has bandwidth borrowing enabled.
Table 136 Bandwidth Borrowing Example
BANDWIDTH CLASSES AND BANDWIDTH BORROWING SETTINGS
Root Class: Administration: Borrowing
Enabled
Sales: Borrowing Disabled Sales USA: Borrowing
Enabled Bill: Borrowing Enabled
Amy: Borrowing Disabled
Sales Asia: Borrowing
Disabled Tina: Borrowing Enabled
Fred: Borrowing Disabled
Marketing: Borrowing
Enabled
Research: Borrowing
Enabled Software: Borrowing
Enabled
Hardware: Borrowing
Enabled